1. Technical Field
The present invention concerns an air-cooled V-shaped engine and more particularly relates to an air-cooled V-shaped engine able to enhance a cooling efficiency of a cylinder and a cylinder head and alleviate the labor burden taken for cleaning the engine.
2. Background Art
An example of the conventional air-cooled V-shaped engines comprises a crank case from which cylinders project slantwise upwards in a left and right direction, when seen from the front in a direction parallel to a center axis of a crank shaft, and cylinder heads attached to the respective cylinders to form a main body of the engine. A fan case is attached to a front portion of the engine's main body and houses an air-blowing fan and a central cooling-air passage is formed between the left and right cylinders and between the cylinder heads so as to feed the cooling air generated by the air-blowing fan to the central cooling-air passage.
A throttle body and a flow-dividing plate are arranged in front of the central air-cooling passage and the flow-dividing plate is provided in the fan case at a position forwardly of the throttle body and has a bottom-plate portion disposed at a position lower than the throttle body, so that the flow-dividing plate divides the cooling air produced by the air-blowing fan toward the left and right sides of the central cooling-air passage.
The air-cooled V-shaped engine of this type has an advantage that the cooling air produced by the air-blowing fan is divided to near the left and right cylinders as well as the cylinder heads so as to cool them uniformly.
However, in the conventional air-cooled V-shaped engine, a ceiling wall of the fan case has a mid portion arranged just below the throttle body, which mid portion forms a bottom-plate portion of the flow-dividing plate, so that an upper mid portion of the fan case is largely concaved downwardly with the result of causing problems.
The above-mentioned conventional technique has the following problems.    <Problem> The cylinder and the cylinder head are cooled with a low efficiency.
The ceiling wall of the fan case has a mid portion arranged just below the throttle body, which mid portion forms a bottom-plate portion of the flow-dividing plate, so that an upper mid portion of the fan case is largely concaved donwardly. This narrows an outlet for blowing air from the upper portion of the fan case to the central cooling-air passage, thereby enlarging the air-passage resistance of the air-blowing outlet to result in reducing the amount of the air blown to the central cooling-air passage and therefore decreasing the cooling efficiency of the cylinders and the cylinder heads.    <Problem> It takes lots of labor to clean the engine.
Due to the narrow air-blowing outlet from the upper portion of the fan case to the central cooling-air passage, cut pieces of weeds and straws, dust and the like foreign matters (hereafter referred to as only ‘foreign matters’) easily clog the air-blowing outlet to increase the number of cleaning operations for the engine. This puts a large burden for cleaning the engine.